Final answer:
The mesentery proper is a broad fan-shaped fold of peritoneum that suspends the jejunum and the ileum from the dorsal wall of the abdomen.
Step-by-step explanation:
The mesentery proper is a broad fan-shaped fold of peritoneum that suspends the jejunum and the ileum from the dorsal wall of the abdomen. The peritoneum is a serous membrane that holds and supports the abdominal organs. In the case of the mesentery proper, it helps to keep the small intestine (jejunum and ileum) in place.